fredkfchan
Mechanical
- May 20, 2002
- 6
I have a problem about thermal stress on a thick pipe, can anyone can give me a hand to sort it out.
The dimension of the pipe:
Outside diameter = 325mm
Inside diameter = 350mm
Wall thickness = 150mm
Physical properties
Outer surface temperature = 576 degreeC
Inner surface temperature = 350 degreeC
The temperature of the inner pipe changed by time, it will cool down for 2 degreeC per min.
I have calculated the maximum stress (circumferential stress) by using the equation from the “Roark” Temperature Stress 15.6, 16, st = [DT aE / (2(1-n) loge (c/b))] [1- (2c2/(c2 – b2))(loge c/b)]. However, I would like to change the inner surface temperature from constant to variable. By changing the criteria of the temperature, can I still using this equation. Can anyone can give me any suggestions to calculate that.
“Roark” Temperature Stress, 15.6, 17, that is an equation for temperature of outer surface raised at the uniform rate, st = [Eam / (8A(1-n)] [3b2 - c2 - (4c4/(c2 – b2))(loge c/b)], however my situation is inner surface temperature drop. Can I use that?
Can I use the 15.6, 16 equation by changing the DT to produce a set of stress values, then using these points to plot a graph?
The dimension of the pipe:
Outside diameter = 325mm
Inside diameter = 350mm
Wall thickness = 150mm
Physical properties
Outer surface temperature = 576 degreeC
Inner surface temperature = 350 degreeC
The temperature of the inner pipe changed by time, it will cool down for 2 degreeC per min.
I have calculated the maximum stress (circumferential stress) by using the equation from the “Roark” Temperature Stress 15.6, 16, st = [DT aE / (2(1-n) loge (c/b))] [1- (2c2/(c2 – b2))(loge c/b)]. However, I would like to change the inner surface temperature from constant to variable. By changing the criteria of the temperature, can I still using this equation. Can anyone can give me any suggestions to calculate that.
“Roark” Temperature Stress, 15.6, 17, that is an equation for temperature of outer surface raised at the uniform rate, st = [Eam / (8A(1-n)] [3b2 - c2 - (4c4/(c2 – b2))(loge c/b)], however my situation is inner surface temperature drop. Can I use that?
Can I use the 15.6, 16 equation by changing the DT to produce a set of stress values, then using these points to plot a graph?